LAUSR

Abstract In this work, we present a scheme to measure electrical charge by combining a cavity optomechanical system with Michelson interferometer. The optomechanical cavity with a charged movable mirror is placed in one arm of a Michelson interferometer, in which the cavity length is modified due to the Coulomb force between the charged moveable mirror with the unknown charge and the charged body with the known charge, leading to a change in the output of the cavity mode. In addition, a perfectly reflecting mirror is rigidly fixed in the other arm. The unknown electrical charge can be measured by the difference of output intensities in both arms of the Michelson interferometer. The theoretical derivation and the numerical simulation indicate our scheme is more sensitive to the external Coulomb force and the precision of the scheme can reach unity charge, due to resorting to the Michelson interferometer. Besides, the effect of temperature on the sensitivity of electrical charge detector is also discussed.